I think the popular solution was to first FLANK like your life depends on it. (which it does
) Then turn away from it until it is on a near stern-aspect. (this extends your remaining lifetime as much as possible) Drop an active countermeasure for the appropriate depth. Then turn further putting the torpedo on the other side of your stern, and keep on turning. Eventually your maneuvering brings you into the shadow zone of the active countermeasure. Once the line between you and torpedo passes over the countermeasure, the torpedo seems to lock onto the countermeasure instead. And you're safe for a moment until the torpedo passes through the countermeasure and may re-aquire you. You may have to do this multiple times to get out of harms way. Every time trying to get out of the detection cone. Anyway, at close range this is an art, rather than a technique.